Systems and methods for delivering sensory input during a dream state

ABSTRACT

Embodiments of the invention provide apparatus, systems and methods for detecting neurological activity indicative of a dream state of a human. Many embodiments of the invention provide apparatus, systems and methods for detecting neurological activity of a human indicative of a dream state or the onset thereof and delivering an input to the user (such as an audio or other sensory input) during the dream state. Particular embodiments of the invention provide systems and methods for detecting neurological activity indicative of the onset or occurrence of a dream state of a human and delivering an audio or other sensory input during the user&#39;s dream state. The audio input may be used for learning, delivering messages to the user&#39;s subconscious, and/or promoting a state of relaxation.

RELATED APPLICATIONS

This application claims the benefit of priority to Provisional U.S.Patent Application No. 61/784,511, entitled “Systems and Methods forDelivering Sensory Input During a Dream State”, filed Mar. 14, 2013; theaforementioned priority application being hereby incorporated byreference for all purposes. This application is also related toconcurrently filed U.S. patent application Ser. No. 14/211,692, entitled“Systems and Methods for Delivering Sensory Input During a Dream State”which is incorporated by referenced herein for all purposes.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the invention relate to systems and methods for detectionof neural activity in a user's brain. More specifically, embodiments ofthe invention relate to systems and methods for detection of neuralactivity indicative of a dream state of a user. Still more specifically,embodiments of the invention relate to systems and methods for detectionof neural activity indicative of a dream state of a user and thedelivery of an audio or other sensory input to the user during thatdream state.

From Joseph to Sigmund Freud, man has sought to interpret and use hisdreams. Authors and artists alike have claimed to be inspired by them.Van Gough said he dreamed his painting, and painted his dream. WhileShakespeare said “We are such stuff as dreams are made on and our littlelife is rounded by a sleep” (The Tempest, IV.i. 156-158). Howeveroutside of the arts perhaps, no one has succeeded in answering thequestion of how dreams can be used for one's benefit during wakinghours.

A brief discussion will now be presented on sleep and dreams. Throughoutthe period of sleep, humans typically experience dream periods. Dreamperiods (e.g., REM sleep state or paradoxical sleep) compriseapproximately 15%-20% of the evening's sleep and occur with regularityevery 80-100 minutes. While the subject is asleep, however, the bodycontinues to exhibit many characteristic physiological changes. Forinstance, during sleep there are frequent gross body movements orpostural changes. These shifts in position occur with increasedfrequency before and after dream periods, whereas a period of simulatedparalysis occurs during the dream period proper. As a specific example,during human sleep there is a period of increased motor activity beforea dream, a period of relative immobility during the dream, and increasedmotor activity following the dream. This behavior is then repeated80-100 minutes later. “Ethology of Sleep Studied with Time-LapsePhotography: Postural Immobility and Sleep-Cycle Phase in Humans” byHobson in Science, Vol. 201, 1978, pp. 1251-1253, includes the analysisof postural changes occurring during sleep and acknowledges theregularity of dreaming but, never has a means for the utilization andcalibration of gross body movements in predicting dream occurrences beendisclosed. This is also discussed in Advances in Dream Research byElliot Weitzman, Spectrum Publications, 1976.

In addition to the lack of motor movement, there are differences betweena dream state and a non-dream state. In particular during a dreamperiod, a person's audio centers of the brain are active. Because theuser's conscious mind is not active to block sounds heard during thistime, it is frequently the case that external sounds heard during adream state are incorporated into a person's dreams and theirsubconscious. This lack of conscious filtering, could potentially bebeneficial for delivering audio messages to the user for learning, aswell as delivering positive messages to a user's subconscious, such asfor smoking cessation. What is needed though is a system for detectingwhen dreams are occurring and delivering desired audio message duringthat time.

BRIEF SUMMARY OF THE INVENTION

Various embodiments of the invention provide apparatus, systems andmethods for detecting neurological activity indicative of a dream stateof a human. Many embodiments of the invention provide apparatus, systemsand methods for detecting neurological activity indicative of a dreamstate of a human or the onset thereof and delivering an input to theuser such as an audio or other sensory input during the dream state.Particular embodiments of the invention provide apparatus, systems andmethods for detecting neurological activity indicative of the onset oroccurrence of a dream state of a human (e.g., a REM sleep state) duringwhich time the user's brain is receptive to audio input and deliveringan audio input during the user's dream state. The audio input maycorrespond to spoken words, music or sounds or combinations thereof. Theaudio input may be used for one or more of learning, delivering amessage to the user's subconscious, promoting a state of relaxation orcalm or maintaining the user in the REM sleep state (as used herein theword subconscious refers to the user's unconscious mind and/orunconscious mental processes). It may also be used for recording theuser's neural-electric brain activity during a dream state, for example,by delivering a specific audio input which results in a particular brainwave or other neural-electric signal which when detected, is then usedas a prompt to start recording of the user's neural-electric activity.

The specific content (e.g., music, words, sounds, etc.) comprising theaudio input, can be selected by the user, or downloaded from theInternet. It may also be created by an instructor of a particular course(e.g., a language course). In such cases, the content may comprise oneor more lectures which the user listens to each night. The lectures canbe stored in various media formats including, for example MP3 and WAVformat. They also may be stored in various media such as flash driveswhich may be connected to a port on the system, such as a USB port. Inparticular embodiments, the content (e.g., a lecture) can be created byan instructor for an on-line course. In such cases, the content can becontained on or at an internet site. The user can then select thecontent (e.g., a particular lecture) from the site and download it tothe audio storage device. Further, the processor or logic resources inthe system can include the capability to allow the user to view andselect from content files for multiple lectures from a given onlinecourse or multiple courses.

In one or more embodiments, depending on the intended purpose (e.g.,learning), the content may be customized for the user, by the user, by aperson other than the user, or by a computer or combinations thereof.For example, in an application for course learning, the instructor maycustomize the content for a particular user based upon the user'scurrent proficiency and/or progress in the course. In the case ofcomputer customization, the system may contain a software module (e.g.,a customization module) which measures how effectively the user islearning the delivered content after a listening session, and thenmodifies the content to improve and/or optimize learning. Theeffectiveness of learning can be determined based on neurologicalactivity measured by the system during or after a content deliverysession during an REM sleep state. It may also be based upon aproficiency test in the subject material that the user takes the nextday with the results uploaded to the customization module. Themodifications in content can include not only the words in the content(e.g., a vocabulary list in a foreign language), but also variouscharacteristics of the content delivery including for example the speedand pitch of the words or other audio signal.

In another aspect of user customization, the customization module can beconfigured to synchronize and/or modify content delivery based on theusers brain waves or other neurological activity. In specificembodiments, the speed of content delivery can be modified based on acharacteristic of the user's alpha waves. In one specific embodiment,the speed of content delivery can be correlated to a frequency of theuser's alpha waves or other brain wave activity. The correlation may belinear, inverse, first order, second order, etc. Also, in relatedembodiments, a period of content delivery can be synchronized to aperiod of brain wave activity, such as an optimal receptivity period asfurther described below.

In particular embodiments, the system can be configured to detect anddetermine particular periods (herein referred to as “optimal receptivityperiods” or “OR Periods”) within a REM sleep state where the user'sbrain has optimal receptivity to the audio input for learning, etc. anddeliver the audio or other sensory input during those periods. Such ORperiods may correspond to periods when alpha waves are occurring. Thesystem may include modules operable on the logic resources for detectingthe OR period based on detection of alpha waves, or other neurologicalactivity of the user. The OR period can also be preselected to period atthe beginning, middle or end of an REM sleep period (e.g., the first twominutes, the middle two minutes or the last two minutes of an REM sleepperiod. It may also correspond to all or a portion of a particular REMdream period in a sequence of REM dream periods, (e.g., the first,middle or last of a sequence of REM dream periods, and combinationsthereof).

In particular embodiments, the system may also be configured to detectsuch OR periods by looking for changes in the user's brain waves orother neurological activity which occur as a result of the audio (orother sensory input) indicating that the user's brain is hearing orotherwise receptive to the message. In one particular approach for doingthis, the system can send out a standard audio message or other soundknown to produce changes in the users neurological activity indicativeof an OR period (herein defined as an audio ping) and then monitor forsuch changes. An algorithm for implementing such an approach can beintegrated into one or more software modules operable on the logicalresource. A variety of such audio pings may be tested for a given user(or class of users) and then have the system determine a subset whichhas the best correlation (e.g., using various curve fitting or othernumerical methods known in the art) to OR periods. This may be doneduring a learning session where the user listens to range of audiopings. Further in particular embodiments, learning sessions can becustomized for the intended purpose of the audio message (e.g.,learning, promoting a state of relaxation or delivery of a subconsciousmessage).

Also, the system can be configured to be self-learning such that aftereach use, the system analyzes particular audio inputs delivered whichresulted in an OR period and then modifies (e.g., tunes or fine tunes)the audio ping accordingly in the future. In this way, the system cancontinuously improve its effectiveness in achieving the desired resultin the user, (e.g., promoting learning, relaxation, delivering asubconscious message).

In one embodiment, the invention provides a system for delivering audiocontent during a dream state comprising wearable electrodes fordetecting electrical signals of the brain or head (e.g., the eye area)indicative of a dream state; logic resources for analyzing theelectrical signals to determine, for example, when a dream state isoccurring; an audio storage device for storing audio signals and anaudio output device for delivering an audio signal to the user based ona signal from the logic resources. The system may also include circuitryfor processing the electrical signals received from the electrodes.

According to one or more embodiments, the wearable electrodes can bepositioned on a headband (also described herein as a head band device)worn by the user during sleep. The electrodes are configured to measureelectrical activity of the user's brain or head indicative of a dreamstate. They can be positioned in various patterns on the headband inorder to facilitate detection of brain waves and other neurologicalactivity (e.g., such as that from eye movement) of the user indicativeof a dream state such a REM sleep state. Such patterns can include, forexample, sinusoidal, vertical or horizontal patterns (all with respectto the horizontal axis of the head band). The spacing in such patternscan be configured based on the particular areas of the head that theelectrode(s) is placed, and/or the wavelength of brain wave activity. Inone embodiment, the electrodes are attached to the head band in the formof a flexible strip (such as a laminated strip or flex circuit) ontowhich the electrodes are placed (e.g., by photolithography, etching,etc.). In these and related embodiments, the flexible strip can beconfigured to bend and flex with movement of the user's head, forehead,etc. such that the electrodes maintain electrical contact with theuser's skin during head movement.

According to one more or more embodiments, the electrodes can comprise avariety of surface electrodes known in the art for measuring signalsproduced by the electrical discharge of neurons in the related areas ofthe brain or head such as those measured during electroencephalography(EEG), or Electrooculography (EOG) for example. They can be arranged andconfigured to make electrical contact with any area of the headincluding areas with and without hair. In particular embodiments, theelectrodes can be arranged and configured to make electrical contactwith the skin over the forehead and temples so that the user's hair doesnot interfere with signal detection. The electrodes are operably coupledto a processor or other logic resources. The connection can be via adirect connection or they may be coupled to the electrical circuitry forprocessing the signals from the electrodes (e.g., for amplification orother purposes) which is, in turn, coupled to the processor.

In various embodiments, other components of the system can also beattached to or otherwise coupled to the headband. This includes theprocessing circuitry, the processor (or other logic resources), a systempower supply (e.g., a battery) and the headphones (or other audio outputdevice used to deliver the audio signal to the user's ears). In someembodiments the headphone or earpiece can have an integral structurewith the headband and in other embodiments they may be attached.

In one or embodiments, the system may also include electrical circuitryfor processing the electrical signals received from the electrodes. Invarious embodiments, such processing circuitry can comprise one or moreof the amplifier devices such as an op amp and/or pre amp, filterdevices such as a low pass, high pass, or band pass filter device, andsignal conversion device such as an A/D or D/A device. Still othersignal processing circuitry known in the art is contemplated. Further,the processing circuitry can be configured to process the electrical orother signals before or after they are inputted to the processor orother logical resources.

In various embodiments, the logic resources may comprise one or more ofa microprocessor, ASIC, analogue device or solid state device. It (they)may be operably coupled to one or more of the processing circuitry,electrodes, audio storage device and audio output device so as to sendand/or receive signals from each. It can include one or more algorithmstypically in the form of software modules operable on the logicresources for performing various functions. Such functions can includeone or more of the following: i) analyzing the electrical signalsreceived from the electrodes; ii) making a determination if the user isin dream state (e.g., REM sleep state); and iii) commencing the deliveryof an audio signal to the user. Such functions can also includeselecting the particular content of the audio signal (e.g., a lecture ina course), as well modifying and/or customizing the content of the audiosignal as is described herein (e.g., modifying content based on theuser's brain wave activity, progress in learning, etc.). The functionsmay also include other system capabilities described herein.

For processor embodiments, the logic resources may include one moreintegrated devices including for example: i) an A/D converter forconverting analog signals received from the electrodes and/or processingcircuitry into digital signals; ii) a D/A converter for convertingdigital signals into analogue signals (e.g., digital signalscorresponding to audio content); and iii) a memory device for storingone or more software modules and/or content of the audio delivered tothe user. Also, in specific embodiments, the audio storage device can beintegrated into the processor.

The audio storage device can include various digital audio storagedevices known in the art including various audio storage chips such asthose used for various MP3 players. It may also include a flash memoryor other connectable memory which the user can plug into a port (such asa USB port) on the system. In various embodiments, as discussed above,the audio storage device may be integral to the logic resources. Theaudio storage device can also be operably coupled with external devicessuch as a cell phone or tablet computer and/or the internet so as toreceive audio content externally. In alternative embodiments, the audiostorage device is external to the system and can be wirelessly coupledto one or more components of the system using radio frequency (RF) orother wireless communication means. According to one such embodiment,the external audio storage device can comprise a cell phone such as anApple® iPhone™. In a method of using such an embodiment, the user couldplace the audio by their bed allowing the audio storage device towireless download selected content to the processor or other componentof the system worn by the user. In a related variation, the Apple®iPhone™ or other cell phone device can be configured to be utilized asboth the audio storage device and audio output device. In use, suchembodiments eliminate the need for the user to wear a headphoneearpiece, ear bud, etc., for example Instead, the user need only wearthe headband (or other apparatus holding the electrodes) providing forgreater comfort during sleep.

The audio output device can comprise a variety of those known in theart. In preferred embodiments the audio output device is configured tobe placed in close proximity to the user's ears. In particular preferredembodiments, the audio output device can comprise a headphone device orearpiece. Typically, it will be placed near or over both ears, but mayalso be positioned over just one ear, for example, in the case of anearpiece. For embodiments of the invention employing a wearable headbandor similar structure, it may be attached to the headband or may integralto it. For example, in the case of headphones, the headphones may havean integral structure with the headband. The audio output device mayalso be removable and/or positionable on headband. In alternativeembodiments, the audio output device may comprise a speaker on anexternal device which is coupled to the system by wire or wirelessly(the latter described above). For wireless embodiments, the speaker maycomprise a cell phone or tablet device. In such embodiments, the systemand cell phone and/or tablet include communication software (e.g.,BlueTooth™) for establishing a handshake between the two devices.

In an exemplary embodiment of a method of using the invention, the userwould position the headband or other wearable device on their head priorto sleep. In some embodiments, the system may include a prompt to informthe user that electrodes are properly positioned (e.g., usingconductance or resistance measurements). The user may have pre-selectedthe particular audio content to be played during their dreams or theymay do so about the time they put the device on using a plug in audiostorage device, such as a flash drive, and/or MP3 player or wirelessdevice such as a cell phone or MP3 player device (e.g. an iPod™, SanDiskSansa ClipZip™, Creative Zen Stone™). The user then falls asleep.Monitoring of electrical activity indicative of the dream state canbegin once sleep commences (which can be determined by use ofaccelerometers placed on the headband or other wearable embodiments ofthe system to measure changes in body movement indicative of sleep).Alternatively, it may begin based on an input by the user, such as abutton on the headband or signal sent from a wireless device such ascell phone or tablet which is in communication with the system, forexample. Detection of the dream state can be done using severalapproaches or combinations thereof. In one embodiment, detection of thedream state may be done by detecting alpha or similar brain waves of theuser. In another approach, the dream state can be detected by saccadicor other movement of the eyes associated with the dream state usingelectrooculography methods. In yet another approach, detection of thedream state may be achieved by detecting a period of decreased motoractivity of the user (as these are characteristic of a dream state)and/or detecting a period of increased motor activity followed by periodof decrease motor activity. In such embodiments, motor activity maydetected using electrodes placed on the head (e.g., on headbandembodiments) as well as other areas of the body. It may also be detectedby the use of accelerometers placed on the head (e.g., placed on theheadband) or on the other areas of the body (e.g., the hands, arms andlegs). In the latter case, the accelerometers can be attached to theuser's skin by an adhesive or worn on an arm band and/or leg banddevice. Also in various embodiments, combinations of the above methodsmay be used, for example, combining detection of alpha waves withdetection of saccadic eye movement, or combining detection of alphawaves with detection of decrease motor activity or even combiningdetection of alpha wave, saccadic movement and decreased motor activity.

Once the system detects electrical activity indicative of a dream state(e.g., a REM sleep state), it can begin to play the audio content. Insome embodiments, it may wait for a period of optimum receptivity (i.e.,OR period) which may correspond to all or a portion of the REM sleepstate. When the system detects that the user has gone out of a dreamstate (e.g., REM sleep state), it stops playing the content, but thenpicks up where it left off, when it detects that the use has re-enteredthe dream state. In some embodiments, the system may repeat the playingof content from an immediately prior dream period (e.g. 30 seconds, aminute or two or more minutes) to allow the user's brain to be betterable to follow the content. Also, in some embodiments, the system can beconfigured to repeat the same content (e.g., a lecture from a course forlearning related embodiments) within the same dream period or overmultiple dream periods so as to better reinforce the content in theuser's mind and/or subconscious.

To assess the effectiveness of the retention of particular content, theuser may take a test immediately upon waking or sometime thereafter, andthen may enter the results into the system directly or remotely (e.g.,using a wireless device) so that the system can customize one more ofthe content and its delivery characteristics (e.g., speed, volume andwhen it is delivered during the dream state) as is described herein. Insome embodiments, the user may do a training session where no content isdelivered so that the system can collect and interpret electrical signaldata from the user's brain so as to be able to determine when the useris an dream state including for example an REM sleep state and/or periodof optimum receptivity (i.e., OR periods) as is described herein.

Further details of these and other embodiments and aspects of theinvention are described more fully below, with reference to the attacheddrawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front view of a system for delivering an audio input to auser's brain during a dream state according to an embodiment of theinvention.

FIG. 1B is a side view of a system for delivering an audio input to auser's brain during a dream state according to the embodiment of FIG.1A.

FIG. 1C is a front view of a system for delivering an audio input to auser's brain during a dream state according to an embodiment of theinvention.

FIG. 2 is a block diagram illustrating various components of anembodiment of a system for delivering a sensory input to the users brainduring a dream state according to an embodiment of the invention.

FIG. 3 is a graph illustrating correlation of content delivery to one ormore dream state periods of a user according to an embodiment of theinvention.

FIG. 4 is a graph illustrating periods of optimal receptivity occurringduring a dream period according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the invention provide systems and methods fordetecting neurological activity indicative of a dream state of a human.Many embodiments of the invention provide systems and methods fordetecting neurological activity indicative of a dream state of a humanor the onset thereof and delivering an input to the user such as anaudio or other sensory input during the dream state. Particularembodiments of the invention provide systems and methods for detectingneurological activity indicative of the onset or occurrence of a dreamstate of a human (e.g., REM sleep state) and delivering an audio orother sensory input during the user's dream state. The audio input maycorrespond to spoken words, music or sounds or combinations thereof. Theaudio input may be used for one or more of learning, delivering amessage to the user's subconscious, promoting a state of relaxation orcalm or maintaining the user in the REM sleep state. It may also be usedfor recording the user's neural activity during a dream state. Otherrelated applications are also contemplated.

Referring to FIGS. 1A, 1B, 1C, 2, 3 and 4, in one or more embodiments,the invention provides a system 100 for delivering audio content duringa dream state comprising wearable electrodes 102 for detectingelectrical signals 303 e of the brain or head indicative of a dreamstate; logic resources 207 for analyzing the electrical signals todetermine, for example, when a dream state is occurring; an audiostorage device 206 for storing audio signals and an audio output device203 for delivering an audio signal to the user based on a signal fromthe logic resources.

As shown in FIGS. 1A-1C, and in accordance with one or more embodiments,the wearable electrodes 102 can be positioned on a headband 101 worn(also described herein as a headband device) by the user 104 duringsleep. The electrodes 102 are configured to measure electrical activityof the user's brain indicative of a dream state. Typically they will bepositioned on an inner surface of the headband so that they can makedirect contact with the skin, but also may be positioned on an edge ofthe headband or on an outside surface. They can be positioned in variouspatterns on the headband 101 in order to facilitate detection of brainwaves and other neurological activity of the user indicative of a dreamstate such as a REM sleep state. Such patterns can include, for example,sinusoidal, vertical or horizontal patterns (all with respect to thehorizontal axis of the headband) as well as combinations thereof.According to one or more embodiments, the spacing in such patterns canbe configured based on the particular areas of the head 105 that theelectrode 102 are placed, and/or the wavelength of the brain waveactivity to be detected such as alpha waves. Alpha waves occur during anREM dream state and have a frequency range from about 7.5 to 12 Hz (withnarrower ranges from 7 to 8 Hz, 7.5 to 11.5 Hz, 8 to 12 Hz and 9 to 12Hz) and an amplitude of about 20 to 200 μV (with a narrower range of 30to 50 μV). In particular embodiments, the spacing can approximate amultiple of a wavelength of the brainwave activity of the user (e.g.,alpha waves). The multiple may correspond to 1×10⁻⁸, 1×10⁻⁹, 2×10⁻¹⁰,1×10⁻¹⁰ or other value. The multiple may be selected so as to tune theelectrodes as an antenna, phased array or other receiving device so asto enhance detection by the electrodes of the brain waves (e.g., alphawaves) or other neurological activity indicative of a dream state.

In one or more embodiments, the electrodes 102 can be attached to theheadband 101 in the form of a flexible strip (such as a laminated stripor flexible circuit) onto which the electrodes 102 are placed (e.g., byphotolithography, etching, etc.) In these and related embodiments, theflexible strip 111 can be configured to bend and flex with movement ofthe user's head 105, forehead 106, etc. such that the electrodes 102maintain electrical contact with the user's skin during head movementwhile asleep. In this way, system 100 allows dream states to be detectedthroughout the night while the user sleeps.

According to one or more embodiments, the electrodes 102 can comprise avariety of surface electrodes known in the art for measuring signalsproduced by the electrical discharge of neurons in the related areas ofthe brain including, for example electroencephalography (EEG). They canbe arranged and configured to make electrical contact with any area ofthe head 105 including areas with 113 and without 114 hair. Inparticular embodiments, the electrodes 102 can be arranged andconfigured to make electrical contact with the skin over the forehead106 and temples so that the user's hair 113 does not interfere withsignal detection. They may also be configured to be placed in or aroundthe eye area 115 in order to measure movements of the eye such assaccadic eye movement associated with an REM sleep state using forexample, EOG (Electrooculographic/Electrooculography) or other relatedmethod for measuring eye movement. The electrodes 102 are operablycoupled to a processor 207 or other logic resources 207. The connectioncan be via a direct connection or they may be coupled to the electricalcircuitry 204 for processing the signals 211 from the electrodes 202(e.g., circuitry for amplification or other purpose) which is, in turn,coupled to the processor 207.

In various embodiments, other components of the system can also beattached to or otherwise coupled to the headband 101. This includes theprocessing circuitry 204, the processor (or other logic resources) 207,a system power supply (e.g., a battery) 212 and the headphones 108, orearpiece 103 or other audio output device 203 used to deliver the audiosignal to the user's ears. In some embodiments, the headphone 108 orearpiece 103 can have an integral structure with the headband 101 and inother embodiments they may be attached.

The specific content (e.g., music, words, sounds, etc.) comprising theaudio input, can be selected by the user, or downloaded from theInternet. It may also be created by an instructor of a particular course(e.g., a language course). In such cases, the content may comprise oneor more lectures which the user listens to each night. The lectures canbe stored in various media formats including, for example MP3 and WAVformat. They also may be stored in various media such as flash driveswhich may be connected to a port on the system, such as a USB port. Inparticular embodiment, the content (e.g., a lecture or seminar) can becreated by an instructor for an on-line course. In such cases, thecontent can be contained on or at an internet site. The user can thenselect the content from the site and download it to the audio storagedevice 206, depicted in FIG. 2. The processor 207 or logic resources 207in the system 200 can include the capability to allow the user to viewand select from content files for multiple lectures from a given onlinecourse or multiple courses.

In one or more embodiments, depending on the intended purpose (e.g.,learning), the content may be customized for the user. This may be doneby the user, by a person other than the user or by a computer. Forexample, in an application for course learning, the instructor maycustomize the content for a particular user based upon the user'scurrent proficiency and/or progress in the course. For example, for alanguage class, the instructor may include a particular list ofvocabulary words, or particular phrases and even conversations based onthe users progress. For the case of computer customization, the systemmay contain a software module 208 (e.g., a customization module) whichmeasures how effectively the user is learning the delivered contentafter a listening session, and then modifies the content to improveand/or optimize learning. The effectiveness of learning can bedetermined based on neurological activity measured by the system 200during or after a content delivery session during REM sleep. It may alsobe based upon a proficiency test in the subject material that the usertakes the next day with the results uploaded to the customizationmodule. The modifications in content can include not only the words inthe content (e.g., a vocabulary list in a foreign language), but alsovarious characteristics of the content delivery including, for example,the speed and pitch of the words or other audio signal.

In another aspect of user customization, the customization module can beconfigured to synchronize and/or modify content based on the user'sbrain waves or other neurological activity. For example, in specificembodiments, the speed of content delivery can be modified based on acharacteristic of the user's alpha waves. In one or more specificembodiments, the speed of content delivery can be correlated to afrequency of the user's alpha waves or other brain wave activity. Thecorrelation may be linear, inverse, first order, second order, etc. In aspecific case, the speed of content delivery can be increased (e.g.linearly) based on a higher alpha wave frequency (e.g. an increase inthe range of 5 to 20%). Further, dynamic adjustments can be made to thespeed of content delivery, based on changes in the frequency of theuser's alpha wave frequency. In related embodiments, such as shown inFIG. 3, a period of content delivery of the system 300 can besynchronized to a period of brain wave activity, such as an optimalreceptivity period (i.e., OR period) during a dream state period 303 a,303 b.

FIG. 3 shows a graph illustrating a correlation of content delivery toone 303 a or more 303 a, 303 b dream state periods of a user. In thisparticular embodiment, the system 300 can be configured to detect anddetermine particular periods (herein also referred to as “optimalreceptivity periods” or “OR periods”) within a REM sleep state (i.e.,rapid eye movement sleep state) 303 a, 303 b period where the user'sbrain has optimal receptivity to the audio input for activities such aslearning and deliver the audio or other sensory input during thoseperiods. Such OR periods may correspond to periods when alpha waves areoccurring. The system 200, 300 may include software modules (e.g. module208) operable on the logic resources 207 for detecting the OR periodbased on detection of alpha waves, or other neurological activity of theuser. In particular embodiments, the systems 200, 300 can be configuredto detect an OR period based on one or more of the following: i) aperiod of frequency and/or amplitude stability of the user's brain waves(i.e. the frequency and/or amplitude are maintained within a selectedrange); ii) an increase or decrease in frequency of the brain waves;iii) an increase or decrease in amplitude of the alpha brain waves. Forthe first case, the period of frequency stability may correspond to afrequency range between about 7 to about 13 Hz, with narrower ranges of7 to 12 Hz, 7.5 to 11.5 Hz, 8 to 12 Hz, 8 to 11 Hz 9 to 12 Hz and 9 to11 Hz; and the period of amplitude stability may correspond to a rangeof about 20 to 200 μV with a narrower range of about 30 to 50 μV. Inparticularly preferred embodiments, the brain frequency during an ORperiod may correspond to a range between about 7 to 8 Hz, or 7.25 to7.75 Hz. The OR period can also be preselected to a period at thebeginning, middle or end of an REM sleep period (e.g., the first twominutes, the middle two minutes or the last two minutes of a REM sleepperiod. It may also correspond to all or a portion of a particular REMdream period in a sequence of REM dream periods, (e.g., the first,middle or last of a sequence of REM dream periods, and combinationsthereof).

Further, in particular embodiments, the system 400, shown in FIG. 4, mayalso be configured to detect such OR periods 401 during an alphawave/dream state period 402 by looking for changes 404 in the user'sbrain waves or other neurological activity 403 which occur as a resultof the audio (or other sensory input) indicating that the user's brainis hearing the message. In one particular approach for doing this, thesystem 400 can send out a standard audio message or other sound (hereindefined as an audio ping) known to produce changes in the user'sneurological activity 403 indicative of an OR period 401 and thenmonitor for such changes. An algorithm for implementing such an approachcan be integrated into one or more software modules operable on thelogical resource. A variety of such audio pings may be tested for agiven user (or class of users) and then have the system 400 determine asubset which has the best correlation (e.g., using various curve fittingor the numerical methods known in the art (e.g. least squares, cubicspline, fuzzy logic etc.) to OR periods 401 over time. This may be doneduring a learning session where the user listens to a range of audiopings. Further in particular embodiments, learning sessions can becustomized for the intended purpose of the audio message (e.g.,learning, promoting a state of relaxation or delivery of a message tothe unconscious/subconscious mind, etc.).

Also, the system 400 can be configured to be self-learning such thatafter each use, the system 400 analyzes particular audio inputsdelivered which resulted in an OR period 401 and then modifies (e.g.,tunes or fine tunes) the audio ping accordingly in the future. In thisway, the system can continuously improve its effectiveness in achievingthe desired result for the user (e.g., promoting learning, relaxation,delivering a subconscious message).

FIG. 2 shows a block diagram illustrating various components of anembodiment of a system 200 for delivering sensory input to the user'sbrain during a sleep state. In this embodiment, the invention provides asystem 200 for delivering audio content during a dream state (as sensedby the electrodes 202 placed against the skin 201 of the user)comprising wearable electrodes 202 for detecting electrical signals ofthe brain or head indicative of a dream state, logic resources 207 foranalyzing the electrical signals to determine, for example, when a dreamstate is occurring, an audio storage device 205 for storing audiosignals and an audio output device 203 for delivering an audio signal tothe user based on a signal 210 from the logic resources 207. The system200 may also include circuitry 204 for processing the electrical signals211 received from the electrodes 202.

Referring to FIG. 2, the system 200 may also include electricalcircuitry 204 for processing the electrical signals 211 received fromthe electrodes 202. In various embodiments, such processing circuitry204 can comprise one or more of amplifier devices such as an op amp, preamp or differential amplifier; filter devices such as a low pass, highpass, or band pass filter device, and signal conversion device such asan A/D or D/A device. Still other signal processing circuitry known inthe art is also contemplated. Further, in one or more embodiments, theprocessing circuitry 204 can be configured to process the electrical orother signals before or after they are inputted to processor or otherlogical resources 207. Also in various embodiments circuitry 204 can beconfigured to process a variety of bioelectric signals including one ormore of EEG (electroencephalographic) signals as well as EOG(electrooculographaic) signals the later used to detect saccadic orother rapid eye movement associated with a sleep state.

The logic resources 207 may comprise one or more of a microprocessor,ASIC, analogue device or solid state device. It may be operably coupledto one or more of the processing circuitry 204, electrodes 202, audiostorage device 206 and/or a remote audio storage device 205 (e.g., cellphone) and audio output device 203 so as to send and/or receive signalsfrom each. It can include one or more algorithms typically, in the formof software modules 208 operable on the logic resources 207 forperforming various functions. Such functions can include one or more ofthe following: i) analyzing the electrical signals received from theelectrodes; ii) making a determination if the user is in dream state(e.g., REM sleep state), for example, based on the analysis of theelectrical signals received from the electrodes or other inputtedsignal; and iii) commencing the delivery of an audio signal to the user.Such functions can also include the selection of the particular contentof the audio signal (e.g., a lecture in a course), as well modifyingand/or customizing the content of the audio signal as is describedherein (e.g., modifying content based on the user's brain wave activity,progress in learning, etc.). The functions may also include other system200 capabilities described herein. In particular embodiments, logicresources 207 or other component of the system 200 can use variouspattern matching algorithms known in the art for comparing a pattern orwaveform of electrical signals received from electrode 202 s (and/orprocessing circuitry 204) to a pattern, waveform or other characteristicof bioelectric signals (e.g., alpha waves) indicative of a dream state.Further, the pattern or waveform or other characteristic of bioelectricsignals indicative of the dream state may be stored in or otherwiseoperably coupled to logic resources 207 (e.g., by a memory device knownin the art).

For processor embodiments, the logic resources may include one moreintegrated devices including for example: i) an A/D converter forconverting signals received from the electrodes and/or processingcircuitry into digital signals; ii) a D/A converter for convertingdigital signals into analogue signals (e.g., digital signalscorresponding to audio content); and iii) a memory device for storingone or more software modules and/or content of the audio delivered tothe user. In specific embodiments, the audio storage device can beintegrated into the processor.

The audio storage device 206 can include various digital audio storagedevices known in the art including various audio storage chips such asthose used for various MP3 players. It may also include a flash memoryor other connectable memory which the user may plug into a port on thesystem such as a USB port or other connection. In various embodiments,as discussed above the audio storage device 206 may be integral to thelogic resources 207. The audio storage device 206 can also be operablycoupled with external devices such as a cell phone 205 or tabletcomputer and/or the internet so as to receive audio content externally.In alternative embodiments, the audio storage device is external to thesystem 200 and may be wirelessly coupled to one or more components ofthe system 200 using radio frequency (RF) or other wirelesscommunication means. According to one such embodiment, the externalaudio storage device can comprise a cell phone 205 such as an Apple®iPhone™. In a method of using such an embodiment, the user could placethe audio storage device by their bed allowing the audio storage deviceto wireless download selected content to the processor 207 or othercomponent of the system 200 worn by the user. In a related variation,the Apple® iPhone™ or other cell phone device can be configured to beutilized as both the audio storage device 205 and audio output device203. In use, such embodiments eliminate the need for the user to wear aheadphone, earpiece 103 or ear bud, for example. Instead, the user 104need only wear the headband 101 or other apparatus holding theelectrodes 102 providing for greater comfort during sleep.

The audio output device 203 can comprise a variety of those known in theart. In preferred embodiments the audio output device is configured tobe placed in close proximity to the user's ear(s) 107. Typically, theheadphone device will be placed near or over both ears, but may also bepositioned over just one ear, for example, particularly in the case ofan earpiece. In particular preferred embodiments, the audio outputdevice 203 can comprise a headphone device or earpiece 103. Forembodiments of the invention employing a wearable headband 101 orsimilar structure, it may be attached to the headband 101 or mayintegral to it. For example, in the case of headphones, the headphones108 may have an integral structure with the headband 101. The audiooutput device may also be removable and/or positionable on headband 101.In alternative embodiments, the audio output device 203 may comprise aspeaker on an external device which is coupled to the system by wire orwirelessly (the latter described above). For wireless embodiments, thespeaker may comprise a cell phone or tablet device. In such embodiments,the system and cell phone and/or tablet can include communicationsoftware (e.g., BlueTooth™) for establishing handshake connectivitybetween two or more devices.

In an exemplary embodiment of a method of using the invention, the user104 would position the headband 101 or other wearable device on theirhead prior to sleep. In some embodiments, the system 100, 200 mayinclude a prompt to inform the user that electrodes 102 are properlypositioned (e.g., using conductance or resistance measurements). Theuser 104 may have pre-selected the particular audio content to be playedduring their dreams or they may do so now using a plug in audio storagedevice 205 such as a flash drive, and/or MP3 player or wireless devicesuch as a cell phone or MP3 player device (e.g., an iPOD™, SanDisk SansaClip Zip™ or Creative Zen Stone™). The user then falls asleep.Monitoring of electrical activity indicative of the dream state canbegin once sleep commences (by use of accelerometer(s) 109 placed onheadband 101 or other wearable embodiments of the system 100).Alternatively, it may be begin based on an input by the user such as abutton 110 on the headband or a signal sent from a wireless device suchas cell phone or tablet which is in communication with the system 100,for example.

Detection of the dream state can be done using several approaches and/orcombinations thereof. In one embodiment, detection of the dream statemay be done by detecting alpha other brain waves of the user which areassociated with a dream state. Such brain waves can be detected byanalyzing electric signals received from electrodes 102 placed on thehead of the user. In another approach, detection of the dream state maybe achieved by detecting a period of decreased motor activity of theuser (as these are characteristic of a dream state) and/or detecting aperiod of increased motor activity followed by a period of decreasedmotor activity. In such embodiments, motor activity may detected usingelectrodes 102 placed on the head 105 (e.g., on headband embodiments) aswell as other areas of the body. It may also be detected by the use ofaccelerometers 109 placed on the head 105 (e.g., placed on the headband101) or on the other areas of the body (e.g., the hands, arms and legs)which are configured and placed on the user's body so as to detectmovement indicative of motor activity or lack thereof. For areas otherthan the head, the accelerometers can be attached to the user's skin byan adhesive or worn on and arm band and/or leg band device and can beconfigured to wirelessly signal processor 207 or other logic resources207. In some embodiments, inputs from both 102 electrodes (for detectingbrain waves associated with sleep) and accelerometers can be used todetect periods of increased or decreased motor activity. In suchembodiments, software module 208 can be configured to selectively weighthe inputs from the electrodes and accelerometers so as to make adetermination of a dream state. For example, modules 208 may beconfigured to require both a particular waveform 303 w, as well as aminimum level of motor activity as indicated by a threshold level (e.g.,a ceiling) signal from the accelerometers so as to make a determinationif the user is in a dream state. The module 208 may also be configuredto filter out signals from the accelerometers indicative of respirationso that signals do not get used for a determination of motor activityand/or lack thereof.

In yet another approach, a dream state or onset thereof, can be detectedby detecting saccadic or other eye movement associated with a dreamstate. Such eye movement can be detected using EOG methods known in theart and in particular embodiments can be detected from one moreelectrodes 102 placed in the eye area. An additional or alternativeapproach for detecting eye movement may include the use of one or morevideo cameras and the like (which may be placed on headband 101 or otherlocation) that are configured to detect eye movement beneath the closedeyelid. The detection of such eye movement may facilitated by the use ofimage analysis algorithms incorporated to one or more modules 208 (suchmodules can be configured to detect small movements and/or displacementsof the eyelid caused by saccadic or other eye movement associated with adream state). In some embodiments, both detected eye movements and brainwaves can be used to detect a dream state or onset thereof. In suchembodiments, software module 208 can be configured to selectively weighthe inputs from the electrodes used to measure brain waves and eyemovements to make a determination of a dream state. For example, modules208 may be configured to require both a particular waveform 303 w, aswell as a minimum level or particular type of eye movement so as to makea determination if the user is in a dream state.

In an alternative or additional approach, modules 208 can be configuredto determine the occurrence of a dream state or onset thereof frommeasurement of skin impedance. During sleep, the amount of sweating ofthe skin can be decreased markedly, as much as three to four time,according to some researchers (J. Narebsk, Human Brain HomeothermyDuring Sleep And Wakefulness An Experimental: ACTA NEUROBIOL. EXP. 1985,45: 63-75; Hbnane, R., et al 1977. Variations in evaporation and bodytemperatures during sleep in man. J. Appl. Physiol. Respir. EnvironExercise Physiol. 42: 50-55, these papers are incorporated by referenceherein in their entirety for all purposes). This results in both anincrease in skin impedance due to the decrease sweating and an increasein skin temperature. In one or more embodiments, system 100 can beconfigured to measure skin impedance using electrodes 102 and skinimpedance measurement methods known in the art. The electrodes used formeasurement of skin impedance can include those positioned on headband101 or another location on the body, for example, on the torso, arms orlegs. In the latter case, such electrodes can be wirelessly coupled toprocessor 207 or other logic resources 207. For use of electrodespositioned in the headband 101, the electrodes 102 can be one in thesame as those used for measurement of neurological activity of theuser's brain or can be separate and specifically configured for skinimpedance measurement. For embodiments using skin impedance as anindicator of a dream state, module 208 can be configured to look for aspecific increase in skin impedance, for example, a 1, 2, 3 or 4 timesincrease in skin impedance as the predictor of a dream state (e.g., anREM dream state) or onset thereof. In some embodiments, both skinimpedance changes and brain waves can be used to detect a dream state oronset thereof. In such embodiments, software module 208 can beconfigured to selectively weigh the inputs from the electrodes used tomeasure brain waves and skin impedance to make a determination of adream state. For example, modules 208 may be configured to require botha particular waveform 303 w, as well as a threshold increase in skinimpedance (e.g., 1, 2, 3, 4 times etc.) so as to make a determination ifthe user is in a dream state.

In related embodiments, the dream state or onset thereof can be detectedusing, temperature sensors 102 t (e.g., thermisters, thermocouples etc.)placed on the user's forehead or other location on the uses head orbody. In the latter case, the temperature sensors can be wirelesslycoupled to processor 207 or other logic resources 207. For forehead andhead placement, the temperatures sensors 102 t can be positioned onheadband 101. In some embodiments, both skin temperature and skinimpedance can be used to detect a dream state (e.g., REM dream state),or onset thereof. In such embodiments, software module 208 can beconfigured to selectively weigh impedance inputs from electrodes 102(used as impedance sensors) and temperature sensors 102 t. Further, adream state may be determined based on a combination of an increase inskin impedance and skin temperature. In specific embodiments, the modulecan be configured to determined based on specific increases in skinimpedance (e.g., 1, 2, 3, 4 times etc.) and specific increase in skintemperature (e.g., 0.5, 1, 2, 3, 4 degrees Fahrenheit).

With reference to FIG. 3, an explanation will be presented of how andwhen the system delivers audio content. When the user is a non-dreamperiod, the system is in a non-play period 301, such as non-play period301 a before a dream state/period. However, once the system 300 detectsa dream state 303 a, 303 b (e.g., an REM sleep state), it begins to playan audio content signal 302 during an audio signal play period 302 a.Detection may be based on analysis of electrical activity 303 e of thebrain or head (e.g., from motion of the eye) or other input such as thatfrom the accelerometers, temperature sensors, etc., indicative of adream state. In some embodiments, the system may wait for a period ofoptimum receptivity (i.e., OR period) which may correspond to all or aportion of the REM sleep state 303 a, 303 b before the start of contentdelivery. When the system 300 detects that the user has gone out of adream state 303 a, it stops playing the content during a subsequentnon-play period 301 b, but then starts playing during a subsequentperiod 302 b, picking up the audio content signal 302 where it left off,when it detects that the use has re-entered the dream state 303 b. Insome embodiments, the system 300 may repeat the playing of content froman immediately prior dream period (e.g., repeating about 30 seconds, aminute or two or more minutes of the prior audio content period) toallow the user's brain to be better able to follow the content. Also, insome embodiments, the system 300 can be configured to repeat the samecontent (e.g., a lecture from a course for learning related embodiments)within the same dream period 303 a or over multiple dream periods 303 a,303 b so as to better reinforce the content in the user's mind.

According to one or more embodiments, to assess the effectiveness ofretention of the particular content, the user may take a testimmediately after waking or sometime thereafter, and then may enter theresults into the system directly or remotely (e.g., using a wirelessdevice) so that the system can customize one more of the content and itsdelivery characteristics (e.g., speed, volume and when it is deliveredduring the dream state) as is described herein. In some embodiments, theuser may do a training session where no content is delivered so that thesystem can collect and interpret electrical signal data from the user'sbrain so as to able to determine when the user is an dream stateincluding, for example, a REM sleep state and/or period of optimumreceptivity as is described herein. In other embodiments, an OR periodmay be determined for a given user by delivering content (e.g. alecture) over selected portions of an REM dream state (e.g. thebeginning middle or end) and then administering tests afterwards todetermine during which period of the user had the best retention ofcontent.

CONCLUSION

The foregoing description of various embodiments of the invention hasbeen presented for purposes of illustration and description. It is notintended to limit the invention to the precise forms disclosed. Manymodifications, variations and refinements will be apparent topractitioners skilled in the art. For example, embodiments of the systemcan be sized and otherwise adapted for use with children taking intoaccount different head sizes and/or brain wave patterns of children,including those of young children (e.g., toddlers and even infants).Also in various embodiments, the delivery of other sensory input to theuser's brain during a dream state is also contemplated (e.g., haptic(feel), visual, taste and smell).

Elements, characteristics, or acts from one embodiment can be readilyrecombined or substituted with one or more elements, characteristics oracts from other embodiments to form numerous additional embodimentswithin the scope of the invention. Moreover, elements that are shown ordescribed as being combined with other elements can, in variousembodiments, exist as standalone elements. Hence, the scope of thepresent invention is not limited to the specifics of the describedembodiments, but is instead limited solely by the appended claims.

What is claimed is:
 1. A system for delivering audio content to a userduring a dream state, the system comprising: a plurality of electrodespositionable on the head of the user, the electrodes configured todetect electrical signals of the user's brain or head indicative of thedream state; logic resources operably coupled to the plurality ofelectrodes, the logic resources configured to analyze the electricalsignals to determine: i) when the dream state occurs; and ii) a periodof optimal receptivity to learning (PORL) from an audio signal to theuser during the dream state based on a period of stability of at leastone of a frequency or voltage of the electrical signals; an audiostorage device operably coupled to the logic resources; the storagedevice configured to store audio content to be delivered to the user; anaudio output device operably coupled to at least one of the logicresources or the audio storage device, the audio output deviceconfigured to output an audio signal to the user containing the audiocontent; and wherein the logic resources are configured to control theaudio output device so as to synchronize the output of the audio signalto the user with the PORL.
 2. The system of claim 1, further comprisingcircuitry for processing the electrical signals.
 3. The system of claim2, wherein the processing circuitry comprises an amplifier or anoperational amplifier.
 4. The system of claim 2, wherein the processingcircuitry comprises a filter, a high pass filter, a low pass filter or aband pass filter.
 5. The system of claim 2, wherein the processingcircuitry comprises a signal converter, an A/D converter or a D/Aconverter.
 6. The system of claim 1, where the audio output devicecomprises an earpiece or headphones.
 7. The system of claim 1, where theaudio output device comprises an external device.
 8. The system of claim7, where the audio output device is wirelessly coupled to at least oneof the logic resources or the audio storage device.
 9. The system ofclaim 8, where the audio output device is a speaker in a portableelectronic device, cell phone or tablet device.
 10. The system of claim1, wherein the plurality of electrodes are disposed on a flexiblematerial which bends and flexes with movement of the user's head tomaintain electrical contact of the electrodes with the user's skinduring movement of the user's head.
 11. The system of claim 1, furthercomprising a headband device configured to be worn on the user's head,the electrodes disposed on the headband.
 12. The system of claim 11,wherein the headband is configured to bend and flex with movement of theuser's head to maintain electrical contact of the electrodes with theuser's skin during movement of the user's head.
 13. The system of claim11, wherein the plurality of electrodes are disposed on an interiorsurface of the headband.
 14. The system of claim 11, wherein at leastone of the logic resources, audio storage device and audio output deviceare attached to the headband.
 15. The system of claim 11, wherein theaudio output device is integral to the headband.
 16. A method fordelivering an audio input to a user during a dream state, the methodcomprising: detecting through use of logic resources electrical activityof a user's brain indicative of the dream state or the onset of thedream state; wherein the detecting includes detecting a period ofoptimal receptivity to learning (PORL) from an audio signal to the userduring the dream state based on a period of stability in at least one ofa frequency or voltage of the detected electrical activity; anddelivering audio input to the user in response to the detection of theelectrical activity indicative of the dream state; wherein the deliveredaudio input is synchronized with the PORL.
 17. The method of claim 16,wherein the audio input comprises spoken words.
 18. The method of claim17, wherein the spoken words contain content used for learning by theuser.
 19. The method of claim 18, wherein the spoken words comprise alecture on a subject to be learned by the user.
 20. The method of claim18, wherein the dream state corresponds to a REM sleep state.
 21. Themethod of claim 18, further comprising: detecting electrical activity ofthe user's brain indicative of a period of optimal receptivity by theuser to content contained in the audio input; and wherein the audioinput is delivered during the period of optimal receptivity.
 22. Themethod of claim 21, wherein the electrical activity of the user's brainindicative of the period of optimal receptivity comprises alpha brainwaves.
 23. The method of claim 21, wherein the period of optimalreceptivity comprises a portion of a period of a REM sleep state. 24.The method of claim 23, wherein the portion of the period of the REMsleep state comprises the beginning, middle or end of the period. 25.The method of claim 21, wherein the detection of the period of optimalreceptivity is made based on analysis of sensed electrical activity ofthe user's brain when a test acoustic output signal is delivered to theuser's ears.
 26. The method of claim 18, wherein the dream state isdetected by detecting a period of decreased motor activity of the user.27. The method of claim 18, wherein the dream state is detected bydetecting a period of increased motor activity followed by a period ofdecreased motor activity.
 28. The method of claim 18, wherein thedetection of the user being in a dream state or dream state onset isperformed using logic resources.
 29. The method of claim 16, wherein theelectrical activity indicative of the dream state comprises alpha brainwaves.
 30. The method of claim 16, wherein the electrical activity ofthe user's brain is detected using electrodes positioned on the user'shead.
 31. The method of claim 30, wherein the electrodes are placed in apattern on the user's head to facilitate detection of electricalactivity indicative of the dream state.
 32. The method of claim 30,wherein the electrodes are positioned on the user's forehead or face.33. The method of claim 30, wherein the electrodes are positioned on aheadband device worn by the user.
 34. The method of claim 16, wherein afrequency during the period of stability in frequency of the electricalsignals is in a range from 7 to 13 Hz.
 35. The method of claim 34,wherein the frequency during the period of stability in frequency of theelectrical signals is in a range from about 7.5 to 11.5 Hz.
 36. Themethod of claim 16, wherein a voltage during the period of stability involtage of the electrical signals is in a range from 20 to 200 μV. 37.The method of claim 36, wherein the voltage during the period ofstability in voltage of the electrical signals is in a range from 30 to50 μV.